The adrenergic neuron of the rat superior cervical ganglion will, under certain culture conditions, express cholinergic characteristics. We request support for experiments directed to the following questions regarding this form of neuronal plasticity. Which adrenergic characteristics are retained (or lost) when neonatal adrenergic, autonomic neurons are maintained in tissue culture conditions which induce the expression of cholinergic properties? What types of neuronal response (to injury or nutritional deprivation) permit more mature adrenergic autonomic neurons to express cholinergic function? The experiments proposed include (among others) time course studies of the activities of choline acetyltransferase (ChAc) tyrosine hydroxylase (TH) and dopamine-beta-hydroxylase (DBH) in cultured neurons accruing cholinergic characteristics. We will also undertake immunocytological staining of neurons demonstrated by electrophysiological methods to be cholinergic. The time course of the ability of neurons established in this culture environment to release norepinephrine (NE) will also be studied. We will continue our ongoing studies on adrenergic neurons established in culture from adult rats. Experiments to define conditions which will allow adult adrenergic autonomic neurons to express cholinergic characteristics will include: 1) exposing adult neurons established as explant cultures to varying degrees of injury to test the hypothesis that cholinergic induction occurs only after severe injury and 2) modifying our methods of preparing adult neurons for culture to determine if efforts to spare that neuron from severe injury permits the preparation of neurons which will not respond to cholinergic induction.